This documentation page applies to an outdated major AMT version. We show it for archival purposes only.
Click here for the documentation menu and here to download the latest AMT (1.6.0).
function [results] = moore1997(inSig,fs)
%MOORE1997 - Loudness model for stationary signals
% Usage: [results] = moore1997(inSig,fs);
%
% Example:
%
% fs = 32000;
% t = linspace(0,1,fs);
% sig = sin(2*pi*1000*t).';
% inSig = setdbspl(sig,100);
%
% Note that currently fs must be 32000 Hz.
%
% References:
% B. C. J. Moore, B. R. Glasberg, and T. Baer. A Model for the Prediction
% of Thresholds, Loudness, and Partial Loudness. J. Audio Eng. Soc,
% 45(4):224--240, 1997.
%
%
% Url: http://amtoolbox.sourceforge.net/amt-0.10.0/doc/models/moore1997.php
% Copyright (C) 2009-2020 Piotr Majdak and the AMT team.
% This file is part of Auditory Modeling Toolbox (AMT) version 0.10.0
%
% This program is free software: you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation, either version 3 of the License, or
% (at your option) any later version.
%
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
% GNU General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with this program. If not, see <http://www.gnu.org/licenses/>.
% AUTHOR: Thomas Deppisch
%% model
fVec = 20:fs/2;
data = data_glasberg2002('tfOuterMiddle1997','fieldType','free','fVec',fVec);
% filter order as in glasberg2002
order = 4096;
% create FIR filter
tfLinear = 10.^(data.tfOuterMiddle/10);
outerMiddleFilter = fir2(order, linspace(0, 1, length(fVec)), tfLinear);
earSig = filtfilt(outerMiddleFilter,1,inSig); % why does filter(..) not work?
% compute fft
spect = fft(earSig);
fftLen = length(spect);
binWidth = fs/(fftLen+2); % bandwidth in Hz represented by 1 fft frequency bin
oneHz = (fftLen+2)/fs; % number of frequency bins representing 1Hz
numBins = round(fftLen/2+1);
compInt = 2*abs(spect(1:numBins)).^2/(numBins*fs); % psd
compdB = 10*log10(compInt./(20e-6)^2); % intensity level in dBSPL
compFq = linspace(0,fs/2,numBins);
nPoints = length(compFq);
compErb = fc2erbN(compFq);
% calculate ERB numbers corresponding to ERB mid frequencies
erbStep = 0.25;
erbFcMin = 50;
erbFcMax = 15000;
erbNMin = fc2erbN(erbFcMin);
erbNMax = fc2erbN(erbFcMax);
erbN = erbNMin:erbStep:erbNMax; % numbers of erb bands
erbFc = erbN2fc(erbN); % center frequency of erb bands
erbLoFreq = erbN2fc(erbN-0.5); % lower limit of each ERB filter
erbHiFreq = erbN2fc(erbN+0.5); % upper limit of each ERB filter
%calculate intensity for each ERB (dB/ERB)
for ii=1:length(erbFc)
range = round(erbLoFreq(ii)*oneHz):round(erbHiFreq(ii)*oneHz);
erbInt(ii) = sum(compInt(range)); % intensity sum in each erb
end
erbdB = 10*log10(erbInt./(20e-6)^2); % intensity level in each erb using reference SPL of 20 uPa
p511 = 4*1000/f2erb(1000); % p for fc=1kHz and a level of 51dB (at 1kHz filters are symmetrical)
erbdB2F = interp1([0 erbFc fs/2], [min(erbdB) erbdB min(erbdB)], compFq); % map erbFc to compFq
for e = 1:length(erbN)
erb = f2erb(erbFc(e));
p51 = 4*erbFc(e)/erb;
intensity = 0;
for comp = 1:nPoints
g = (compFq(comp)-erbFc(e))/erbFc(e);
if g<0
p = p51 - 0.35*(p51/p511) * (erbdB2F(comp)-51);
else
p = p51;
end
g = abs(g);
w = (1+p*g)*exp(-p*g);
intensity = intensity+w*compInt(comp); %intensity per erb
end
eL(e) = intensity;
end
results.eLdB = 10*log10(eL./(20e-6)^2); % get dB SPL (20uPa reference)
results.erbN = erbN;
%% calculating specific loudness
dataSL = data_glasberg2002('specLoud','fVec',erbFc);
tQdB = dataSL.tQ;
tQ = 10.^(tQdB./10);
tQdB500 = dataSL.tQ500;
gdB = dataSL.g; % low level gain in cochlea amplifier
g = 10.^((tQdB500-tQdB)/10);
a = dataSL.a; % parameter for linearization around absolute threshold
alpha = dataSL.alpha; % compressive exponent
c = dataSL.c; % constant to get loudness scale to sone
specLoud = zeros(size(eL));
specLoud1 = c*(2*eL./(eL+tQ)).^1.5 .*((g.* eL + a).^alpha-a.^alpha);
specLoud2 = c * ((g .*eL + a).^alpha - a.^alpha);
specLoud3 = c*(eL./1.04e6).^0.5;
specLoud(eL<tQ) = specLoud1(eL<tQ);
specLoud(eL<=10^10 & eL>tQ) = specLoud2(eL<=10^10 & eL>tQ);
specLoud(eL>10^10) = specLoud3(eL>10^10);
%% monaural/binaural loudness (= instantaneous loudness), short term loudness (STL), l